Hi @ozopled, I assume you are trying to use the 4C in conjunction with the Tobii Pro SDK Python Bindings?
I am afraid that do this, you need to purchase the special analytical use licence and a provided unlock file that will allow the Pro SDK to read data from the 4C.
To request a quote, please contact Tobii Pro Sales @ https://www.tobiipro.com/contact/sales/
The Tobii Interaction API however (https://developer.tobii.com/consumer-eye-trackers-interaction-library/) is free to use as is the
Unreal Engine SDK and Core SDK.
Apologies for any inconvenience and thanks for your understanding.